chore: rename .yaml extensions to .yml for consistency

roles/proxmox-lxc-provision/tasks/start.yml

@@ -0,0 +1,11 @@
+---
+- name: Start the LXC container
+  community.general.proxmox:
+    <<: "{{ proxmox_api_connection }}"
+    vmid: "{{ lxc_result.vmid }}"
+    state: started
+  register: start_result
+  retries: 3
+  delay: 5
+  until: start_result is success
+  failed_when: start_result.failed and ('already running' not in start_result.msg)